The present invention relates to an information reading device or optical pickup for optically reading recorded information from an information storage medium such as a compact disk (CD), a laser vision disk (LVD), or the like, and more particularly to a skew adjusting mechanism for use in such an optical pickup.
Recorded information stored in optical information storage mediums such as CDs, LBDs, or the like is reproduced by CD players, LVD players, or the like. The CD players and the LVD players have an optical pickup for optically reading recorded information from a disk. The optical pickup has a laser diode for emitting a laser beam to read recorded information. The laser beam generated by the laser diode is focused into a beam spot on the information recording surface of the disk by an objective lens. The laser beam thus applied as a beam spot to the information recording surface of the disk is reflected thereby as a light beam bearing information represented by pits on the disk. The reflected light beam goes through the objective lens to a photodetector, which converts the light beam into an electric RF signal for the reproduction of the recorded information.
The optical pickup is required to apply the laser beam as a sufficiently small beam spot to the information recording surface of the disk. To meet this requirement, the optical pickup has to be mounted in the player in a proper position or a attitude so that the optical axis of the optical pickup extends perpendicularly to the information recording surface of the disk and the laser beam will not be defocused on the disk due to aberrations of the objective lens. When the player is assembled, therefore, the position or inclination of the optical pickup or objective lens is adjusted through a process known as skew adjustment in order to minimize the aberrations of the objective lens and any deviation of the optical axis of the optical pickup. Such skew adjustment is made by a skew adjusting mechanism on a base of the optical pickup.
One conventional skew adjusting mechanism has three adjusting screws which supports an objective lens supporting device on the base of the optical pickup. The operator adjusts the height of the points where the objective lens supporting device is supported by the adjusting screws by turning the adjusting screws, thereby setting the objective lens for a desired focal length and inclination.
The prior skew adjusting mechanism however requires a complex, tedious, and time-consuming adjusting procedure since fine adjustments have to be repeated using the three adjusting screws until proper objective lens position and inclination are achieved.